Basically, here’s what that means: if you haven’t used an app for a set number of days, Android will consider it an inactive app. And the operating system will free up disk space by basically removing that app from your device’s Dalvik compiler cache.

That means when you do run it again, it’ll need to be re-optimized. It also means that you won’t save any space if you do regularly use every app on your device. So this feature probably isn’t going to free up a ton of space on your device… but if you’ve got a phone without a lot of built-in storage, every megabyte helps.

It could take a while before we start to see this feature in the wild. It won’t be widely available until Android 8.1 is released… and many existing phones will probably never receive an Android 8.1 update.